Procollagen will be isolated and purified using the skins of bovine fetuses as a source of the procollagen. Salt precipitation, agarose column chromatography, preparative gel electrophoresis, and isoelectric focusing will be employed for the purification. Purity and molecular weight determinations will be conducted by physical-chemical techniques. The non-collagenous portion of procollagen will be studied to determine the amino acid content and the content and structure of the sugar residues. The possibility that amyloid is derived from the non- collagenous portion of procollagen will be investigated by structural and immunological techniques.